Abstract: A CO₂ inverter welding system with waveform control is established,in which the TMS320C240 digital signal processing (DSP) is adopted as the central controller.The structure of the system is introduced,and the working principle of the subsystems are given in detail,such as the main circuit,multi-system of DSP,setting system of the welding parameters,and the wire feeding system and the welding sequence control circuit.The output characteristic is controlled using a collateral double close-loop method,which is fulfilled by software.The principle of this control method and the output waveform are given.The results show that besides its simple structure and easy operation,the system has good controlling performance.